Abstract

Acrotriche serrulata exhibits a complex and uncommon form of flowering. It starts with a male-phase flowerthat shows secondary pollen presentation on the perianth and follows with a female phase after the corolla isremoved or abscissed. We examined the potential for insects, lizards, and mammals to act as pollinators.Observations and experiments on breeding system, phenology, floral scent, flower visitors, and lizard feedingwere undertaken in southern Australia. Acrotriche serrulata sets little fruit by autonomous selfing but readily setsfruit after facilitated geitonogamy and xenogamy. Flower anthesis is diurnal and nocturnal. The nectar profileincludes acetaldehyde, ethanol, and ethyl acetate. The nocturnal mammals Trichosurus vulpecula and theintroduced Rattus rattus were the only visitors observed to actively forage on the flowers. In contrast, the skinksEgernia whitii, Niveoscincus ocellatus, and Niveoscincus metallicus routinely passed flowers full of nectar andforaged only on those presented during feeding observations. Insects visited the flowers but did not behave aspollinators. Acrotriche serrulata is likely to be pollinated by nocturnal mammals attracted to its flowers by scent.Effective pollinators appear to be rare over some of its range. This may have implications for the long-termreproductive success and conservation of A. serrulata.